Method of seaming vinyl-backed materials



Nov. 23, 1965 w. H. STUDER ETAL 3,219,508

METHOD 0F SEAMING VINYL-BACKED MATERIALS Original Filed May 2, 1961 MKM@ ATTORNEY United States Patent 3,219,508 hlETHD F SEAMNG VINYL-BACKED B'EATERIALS William H. Studer, Leominster, Mass., and Fredrick R. Cloos, Glen Cove, NX., assignors to United States Rubber Company, New York, N.Y., a corporation of New Jersey Original application May 2, 1961, Ser. No. 107,120. Di-

vided and this application Feb. 13, 1964, Ser. No. 345,555

3 Claims. (Cl. 156-304) This application is a division of our copending application, Serial No. 107,120, filed May 2, 1961, now abandoned.

This invention relates to carpet seaming tapes and more particularly to carpet seeming tapes comprising an extensible backing strip to which transversely extending lengths of continuous filament yarns are attached.

A carpet seaming tape of this general type was disclosed in U.S. Patent No. 2,727,295, issued to Paul D. Wright on December 20, 1955. This patent disclosed a tape in which untwisted yarns of low extensibility and high strength and formed of long or substantially continuous fine filaments are mechanically attached to a longitudinally extensible strip of material by parallel rows of stitches. Such a tape is well suited to seaming the lighter weight carpets.

Recently, however, there have been developed vinyl backed floor coverings for which a heat-sealable seaming tape was found desirable. Vinyls are normally difficult to adhere to, the adhesive bond generally being weaker than the vinyl material itself. Additionally, the adhesives which are available tend to cause staining in vinyl materials which is detrimental when considering carpets. It is also difficult to achieve constant adhesive bond strength because of operator differences, solvent drying conditions, age of adhesives or cements, etc. Furthermore, a considerable length of time must be allowed for evaporation of volatile solvents, which may be hazardous, before the carpet can be placed in use. Therefore, a seaming tape was required that would be free from these difficulties and which would also provide a reliable method of sealing.

Accordingly, it is an object of the present invention to devise a searning tape for vinyl backed carpeting that can be used to join sections of such carpeting by known heat sealing methods.

It is a further object of the present invention to devise such a seaming tape of the general character of that disclosed in the above-mentioned Wright patent, No. 2,727,295. Such a seeming tape has to be inexpensive to manufacture and readily adaptable for the use desired.

In accordance with these objects we have invented a seaming tape for vinyl carpeting or for vinyl backed floor coverings comprising a strip of longitudinally extensible material, to which material yarns made of a plurality of substantially continuous filaments coated with a thermoplastic material are attached. Such yarns extend transversely of the strip in the manner characteristic of tapes of this class. The yarns may be attached to the longitudinally extensible strip of backing material by longitudinal extensible parallel rows of stitches, or they may be attached by heat and pressure to the extensible strip making use of the thermoplasticity of the coating.

The thermoplastic coating on the transversely extending yarns permits the tape to be heat sealed to the vinyl backing of the iioor covering, thus to form a butt joint between the edges of two pieces of carpet that will be longitudinally extensible and contractable, but extremely secure against transverse separation. The yarns, accordingly, will be characterized by having high tensile strength and low elongation, in order to resist the transverse forces to which the tape may be subjected in the seam.

The invention, its objects and advantages are further described in reference to the accompanying drawings, in which:

FIG. 1 is a top plan view of an example of a seaming tape embodying this invention, in which the method of using the tape for seaming together the edges of two pieces of vinyl backed carpeting is illustrated; and

FIG. 2 is a perspective View of the transversely extending yarns used in the tape.

Referring to FIG. l, the tape 10 therein illustrated comprises a strip of longitudinally extensible material 11, to which transversely extending lengths 12 of thermoplastic covered yarns 13 are attached by longitudinal rows of stitches 14. The yarn 13 is formed from a plurality of substantially continuous, relatively inextensible filaments 15, which filaments preferably are made of glass, although other materials having the necessary high tensile strength and low extensibility may be used.

The multi-filament yarns 13 are individually coated with a thermoplastic material 16. (See FIG. 2.) Preferred coating materials are plastisols of polyvinyl chloride or copolymers thereof, although other thermoplastics compatible with, and having similar softening temperatures as, the vinyl carpet backing material to which the seaming tape 10 is applied may be used. The preferred material may be described in more detail as a vinyl chloride resin, in which category we include polyvinyl chloride resin itself, as well as copolymers of vinyl chloride with a minor proportion (c g., 1%to 40%) of another copolymerizable rnonoethylenically unsaturated monomer, such as vinyl acetate, vinylidene chloride, diethyl maleate or the like, as well as mixtures of polyvinyl chloride resin wih the aforementioned copolymers. Furthermore, it is possible to use both a plasticized polyvinyl chloride resin, or a plastisol of vinyl chloride. A plasticized polyvinyl chloride would be used with extrusion methods of coating filaments, while a plastisol vinyl coating would be used in the manufacture of coated filaments by dipping methods. A vinyl plastisol formulation found suitable is as follows:

Ingredients: Parts by weight Polyvinyl chloride 20 Copolymer of PVC and diethyl maleate (9S-2) 80 Plasticizer-dicapryl phthalate Plasticizer-unsaturated naphthenic hydrocarbon 50 Vinyl stabilizer-organic cadmium compound 3 Filler-calcium carbonate 50 Wetting agent-lecithin 2 A coating 0.004 to 0.006 inch thick has been found to work satisfactorily. It should be recognized that there is virtually no upper limit to the thickness of coating useable on the yarns, but the minimum thickness should be 0.004 inch, with a preferred minimum being 0.006 inch.

The longitudinally extensible backing strip 11 is preferably made of a porous non-Woven fabric material, the type known as a uni-directional fabric having been found to be the most satisfactory. The fibers 17 in the porous uni-directional fabric preferably run parallel to the thermoplastic coated yarns, that is, in the transverse direction of the tape. The fibers 17 may themselves be made of a thermoplastic material.

When the fibers 17 in the uni-directional non-woven fabric strip run parallel to the thermoplastic coated yarns 13, there is absolutely no force opposing longitudinal movement of the carpet material. Also when seaming circular seams or irregular inserts in the carpet, it would be very difficult to 4apply the tape smoothly around the f 3 contours of the seams where the fibers 17 in the nonwoven strip 11 run longitudinally of the tape, or perpendicularly to lthe thermoplastic covered yarns 13. However, Where they run parallel t-o the direction of the yarns, that is, in the transverse direction of the tape, it i-s easy to seam even a very tight circle with the tape, thus alleviating the necessity `of cutting short lengths of Itape to seam 1a circular insert. A uni-directional non-woven fabric suitable for use as a material from which the strip 11 can be made is ISold under the brand name Viskon and is manufactured by Chicopee Mills.

The rows of stitches 14 are made of rayon, although other fibers, or even thermoplastic fibers, can be used. In the 11/2 inch wide tape illustrated in lFIG, 1, three such rows 14 are used, two where the yarns 13 form loops 1S near -the marginal edges of the strip 11 and one running down the centerline 19 of the tape.

It should be understood that the coated yarns 13 may be held in place lon strip 11 by means other than stitching. For instance, they may be attached by use of adhesives or by the adhesion inherent in the thermoplastic coating -16 itself. In the latter case, a very light applicati-on of pressure and heat to the coated yarn will cause it to adhere to the backing strip `11, providing the strip does not have a release coating itself.

=FIG. l illustrates use of the tape 10 for securing the i edges 20 of two pieces of vinyl backed carpet 21 together. The edges 20 of the carpet 21 -are butted together and laid down yonto the tape 10 along the centerline 19 thereof, thus to form a seam 22 in the carpet along `such line. Application of heat and pressure with any of several wellknown means seals the thermoplastic coating 16 on the yarns 13 to the vinyl backing 23 of the floor covering. The vinyl of the carpet backing strikes through the porous non-woven backing strip 11, indicating proper adhesion between the two materials. It `should be noted that the vinyl backing 23 does not itself seal the edges 20 of the two pieces of carpet together. Rather, it serves to indicate when the joining is satisfactorily completed. As the hot vinyl oozes through the porous backing, it causes strip 11 to become shiny, lled with vinyl, and to change its color to that of the backing 23. When this occurs, it signals the completion of a satisfactory seam.

The high tensile strength of the glass fibers 15 and the low extensibility characteristic of this material prevent any transverse separation along seam 22. Likewise, the longitudinal extensibility of the tape 10 produces :a floor covering free from irregularities Iand of smooth and even appearance. The longitudinal extensibility of the strip "11 permits the marpeting to be stretched lengthwise without rupturing the tape 10. The seam can also contract longitudinally as the carpet strinks. Yet the substantial inextensibility of the yarns 13 prevents the seam 22 from opening up.

While the preferred form of this invention has been described With respect to a carpet seaming tape, it should be recognized that la seaming -tape of the type described could also be used with any vinyl backed material, such as a vinyl coated fabric, or even with unsupported polyvinyl sheet materials, either flexible or rigid. It should be further understood that changes may be made without departing from the spirit of the invention and that it is intended to'cover all such changes coming within the scope of the following claims.

Having thus described our invention, whatwe claim and desire to protect by Letters Patent is:

1. The method of seaming sheet materials having vinyl backings, comprising the steps of placing two edges of respective sections -of said sheet material to be seamed in abutting juxtaposed relation to each other, applying to the vinyl 'backing along and in bridging relation to the butt joint between said edges a longitudinally extensible porous non-woven fabric tape having relatively inextensible filamentary strands individually coated with a thermoplastic material compatible with vinyl attached thereto in transverse relation to said tape and so as to extend across said butt joint between said edges, applying heat and pressure to said sheet material sections and said tape along said butt joint sufliciently to seal said thermoplastic material to said vinyl backing, and maintaining said heat and pressure until said vinyl backing strikes through said tape to indicate completion of the seam.

2. The method of claim 1, in which s-aid heat and pressure are maintained until said vinyl backing lls said porous tape sufficiently to cause the same to change its color to that of said vinyl backing.

3. The method of claim 1, in which said heat and pressure are maintained until said vinyl backing lills said porous tape sufiiciently to cause the same to become shiny.

References Cited by the Examiner UNITED STATES PATENTS 2,391,731 l2/1945 Miller et al 156-304 2,523,865 9/1950 Dildilian 156-304 2,727,295 12/1955 Wright 156-304 ALEXANDER WYMAN, Primary Examiner. EARL M. BERGERT, Examiner. 

1. THE METHOD OF SEAMING SHEET MATERIALS HAVING VINYL BACKINGS, COMPRISING THE STEPS OF PLACING TWO EDGES OF RESPECTIVE SECTIONS OF SAID SHEET MATERIAL TO BE SEAMEN IN ABUTTING JUXTAPOSED RELATION TO EACH OTHER, APPLYING TO THE VINYL BACKING ALONG AND IN BRIDGING RELATION TO THE BUTT JOINT BETWEEN SAID EDGES A LONGITUDINALLY EXTENSIBLE POROUS NON-WOVEN FABRIC TAPE HAVING RELATIVELY INEXTENSIBLE FILAMENTARY STRANDS INDIVIDUALLY COATED WITH A THERMOPLASTIC MATERIAL COMPATIBLE WITH VINYL ATTACHE D THERETO IN TRANSVERSE RELATION TO SAID TAPE AND SO AS TO EXTEND ACROSS SAID BUTT JOINT BETWEEN SAID EDGES, APPLYING HEAT AND PRESSURE TO SAID SHEET MATERIAL SECTIONS AND SAID TAPE ALONG SAID BUTT JOINT SUFFICIENTLY TO SEAL SAID THERMOPLASTIC MATERIAL TO SAID VINYL BACKING, AND MAINTAINING SAID HEAT AND PRESSURE UNTIL SAID VINYL BACKING STRIKES THROUGH SAID TAPE TO INDICATE COMPLETION OF THE SEAM. 